2015-12-24: Updated with config changes now that I'm back to using Gnus+dovecot+offlineimap+Gmail

2014-04-09: This post is from 2008. =) I think I used dovecot+offlineimap because Gnus and maildir weren't getting along properly and directly connecting with IMAP to Gmail's server was slow, but things have probably changed a fair bit since then. I eventually moved to using the Gmail web interface for most things, but I still miss my Gnus setup!

Make sure you've set up Postfix or some other mail server that can send mail.

Start Emacs. Start Gnus with M-x gnus. If you don't see the INBOX group, press ^ (gnus-group-enter-server-mode), open nnimap:Mail, move your cursor to the INBOX, and either press RET to go into the group or press u (gnus-browse-unsubscribe-current-group) to toggle the subscription status until you're subscribed to the group. Then it should show up on the group screen (M-x gnus).